A wide range of medical implants are known from the prior art. In conjunction with the present invention, an electromedical implant is understood to be an implant that, besides including a power supply (for example a battery), comprises further electrical and/or electronic components (for example, capacitors, etc.), which are arranged in a housing that is hermetically sealed. Electromedical implants of this type generally include cardiac pacemakers, defibrillators, neurostimulators, leadless pacemakers, cochlear implants or other hermetically encapsulated electronic products, for example.
Implants of this type are often connected to electrode lines, which treat a body after implantation therein, for example, transfer and/or deliver stimulation impulses and/or defibrillator shocks to specific points of the body, or are used to detect electronic potentials of points of the body. For this purpose, an electrical connection has to be produced between the electrical and/or electronic components arranged in the interior of the housing and the electrode line. This electrical connection is generally produced by means of a feedthrough and what is known as a header. A feedthrough is used in this instance to provide at least one electrical connection between the interior of the housing and the exterior environment, and is simultaneously responsible for the hermetic sealing of the housing. The header, fastened via the feedthrough, continues the electrical connection of the feedthrough to a contact point and is used to plug the at least one electrode line into a corresponding, generally standardized socket. Electrical contact between the implant and the connecting piece of the electrode line is thus produced at the contact points of the socket. Alternatively, an electrode line with an electrode may already be integrated into the header.
Ceramic feedthroughs are already known from the prior art, for example, from document European Patent No. EP 1 897 588 B1. With feedthroughs of this type, local metal coatings on ceramics are necessary for the soldering of feedthrough pins and of flanges. The metal solders form menisci and, therefore, the pins cannot be packed very densely due to the necessary insulation paths. It is also disadvantageous that ceramic feedthroughs and headers are joined in separate manufacturing steps to the implant housing and the electrical connections between the feedthroughs and electrical connecting points in the header have to be linked. Electromechanical connecting points or sockets for electrode lines have to be provided by means of plastic headers inclusive of individual metal components, such as, for example, sleeves, strips, etc. When using EMI filters with such a feedthrough, complex joining processes leading to high costs and errors (e.g., soft soldering, adhesive bonding, welding) are used in order to attach EMI filters to feedthroughs. To this end, additional components (e.g., capacitors) that are costly in terms of space are also necessary, inter alia at the feedthroughs themselves or at the connecting strips in the interior of the implant.
The same is also true of the glass feedthroughs or glass/ceramic feedthroughs already known, wherein, with some material combinations of the glass feedthroughs, it is additionally difficult to control the glass solder flux. With both types of feedthrough there are restrictions in terms of the feasible geometry and the selection of the materials due to the generally high soldering temperature and the accompanying coefficients of thermal expansion.
Feedthroughs are known from document German Patent No. DE 10 2009 035 972 A1, which has a collar-like retaining element, an insulation element, and at least one elongate line element. The line element is used to produce the electrical connection between the interior of the housing and the exterior of the implant. The line element of the known feedthrough is characterized in that it has a cermet, that is to say a composite material, formed from ceramic materials in a metal matrix. With this known feedthrough also, the feedthrough and header each have to be produced and joined to the implant housing in separate manufacturing steps, and the electrical connections have to be linked. In the case of a feedthrough, the electrical connection to the adjacent elements is generally produced by pins, that is to say by protruding portions of the line elements. Cermet pins or feedthroughs are brittle, however, and therefore protruding connections may break easily, for example. Cermet pins protruding in a pin like manner, as are disclosed in the above cited document, are considered to be brittle, mechanically unstable connections. Furthermore, with the known feedthrough, the connected flanges of the retaining element are to be turned/milled, which is very complex. In addition, separate cermet pins, in particular running in a straight line, spare space in these feedthroughs. The construction of the known feedthroughs also causes mechanical stress peaks, and there is a potential risk of incorrect functioning of the implant as a result of unfiltered cermet feedthroughs. There is also a risk that the electrical insulation paths in the dense cermet pin arrangement will be too short and that an unsecure connection between the flange/cermet/insulation ceramic will result due to different coefficients of thermal expansion or that it will be impossible to produce the connection due to a necessary high sintering temperature, in particular with use of a “pure” Al2O3 ceramic having degrees of purity of more than 95%, for example, in the cermet feedthrough.
An additional cost is also necessary with use of the above disclosed feedthrough forms, and there is a risk of error during production, connection/activation and implantation of plastic headers. Further, with use of plastic headers, the reference and anchor points have to be joined on (generally welded on) to implant housings in a separate process with additional spatial requirement.
The present invention is directed toward overcoming one or more of the above-identified problems.
An object is therefore to create a connecting device that can be produced in a simple and, therefore, cost-effective manner. A further object is to create a corresponding electromedical implant.